1. Field of the Invention
This invention relates to an automatically locking tubing coupler for attaching one length of tubing to another such length.
2. Disclosure Information
Various devices have been used for the purpose of joining lengths of tubing so as to make mechanically strong and fluid tight joints. Threaded couplings are known in which a ferrule mounted about the exterior of a section of tubing is clamped to a central cylinder or barrel by means of a threaded nut. Although such a device is usually leak tight when properly assembled, errors are easily committed during the assembly process because excessive time and dexterity are required to complete the threaded connections without cross threading the nuts upon the barrel.
Non-threaded connectors have also been employed for the purpose of providing fluid tight connections between tubing lengths. U.S. Pat. Nos. 758,099 and 946,703 as well as British patent No. 0100518 and French patent No. 0794639 all disclose non-threaded couplers involving a central barrel with which the tubing halves to be joined are first engaged, and further including a barbed, plastically deformable spider which is forced into contact with the tubing by means of a hammer or other tool so as to form the completed joint. These devices suffer from the defect that is not always possible to mount the joint in a position allowing the use of the hammer or other tool to fasten the coupling. Another drawback to this particular design stems from the fact that judgment of the hammer operator is required to prevent use of excessive force during the clinching operation. The present invention remedies this deficiency by providing a compact coupling which requires no tool for its final assembly.
U.S. Pat. No. 3,372,949 discloses yet another design for coupling tubes in which the tubes to be joined must be equipped with hubs capable of accepting a cylindrical joint member equipped with O-ring seals. This design is costly and is not suitable for use with thin wall tubing, it being primarily intended for employment with glass laboratory tubing.
U.S. Pat. No. 4,312,551 discloses a pipe fitting for use with electrical conduit in which a nonmetallic coupling is equipped with a metallic conductor strap. No means is disclosed aside from the friction produced by O-rings for axially retaining the joined pipes in registry with the connector. Finally, U.S. Pat. No. 2,924,434 discloses a safety joint for use in oil well drilling. This disclosure is not deemed to be relevant to the present application.